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Search Results: 1 - 10 of 983 matches for " Kensuke Fukuda "
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Rubber Hand Illusion under Delayed Visual Feedback
Sotaro Shimada,Kensuke Fukuda,Kazuo Hiraki
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0006185
Abstract: Rubber hand illusion (RHI) is a subject's illusion of the self-ownership of a rubber hand that was touched synchronously with their own hand. Although previous studies have confirmed that this illusion disappears when the rubber hand was touched asynchronously with the subject's hand, the minimum temporal discrepancy of these two events for attenuation of RHI has not been examined.
A Visualization Tool for Exploring Multi-scale Network Traffic Anomalies
Romain Fontugne,Toshio Hirotsu,Kensuke Fukuda
Journal of Networks , 2011, DOI: 10.4304/jnw.6.4.577-586
Abstract: Since anomaly detection in Internet traffic is a crucial and unmet challenge, many anomaly detectors for backbone traffic have recently been proposed. However, evaluating anomaly detectors is a complicated task due to the lack of ground truth data. Our goal is to provide a good level of support for rapidly understanding traffic behaviors and assisting researchers in evaluating the effectiveness of anomaly detectors. This article presents an interactive tool that takes advantage of several graphical representations highlighting the different aspects of network traffic and anomalies. The proposed tool allows for exploration of network traffic at any temporal and/or spatial (address and port) scales. In addition, an accurate description of any subtraffic is available in the form of textual packet information, enabling complete understanding of the monitored traffic. We exhibit the effectiveness of the proposed tool by analyzing darknet traffic, backbone traffic, and anomalies reported by an anomaly detector. We illustrate a manual validation of the anomalous traffic reported by anomaly detectors, and inspect a recent and sophisticated threat: the Conficker worm. We also state several typical patterns that stand for different kinds of anomalies.
Origin of Critical Behavior in Ethernet Traffic
Kensuke Fukuda,Hideki Takayasu,Misako Takayasu
Physics , 2000, DOI: 10.1016/S0378-4371(00)00452-0
Abstract: We perform a simplified Ethernet traffic simulation in order to clarify the physical mechanism of the phase transition behavior which has been experimentally observed in the flow density fluctuation of Internet traffic. In one phase traffics from nodes connected with an Ethernet cable are mixed, and in the other phase, the nodes alternately send bursts of packets. The competition of sending packets among nodes and the binary exponential back-off algorithm are revealed to play important roles in producing $1/f$ fluctuations at the critical point.
Self-Similar Traffic Originating in the Transport Layer
Kensuke Fukuda,Misako Takayasu,Hideki Takayasu
Physics , 2000,
Abstract: We performed a network traffic simulation to clarify the mechanism producing self-similar traffic originating in the transport layer level. Self-similar behavior could be observed without assuming a long-tailed distribution of the input file size. By repeating simulations with modified TCP we found that the feedback mechanism from the network, such as packet transmission driven by acknowledgement packets, plays an essential role in explaining the self-similarity observed in the actual traffic.
Microarray Analysis of the Effects of Amelogenin on U937 Monocytic Cells  [PDF]
Terukazu Sanui, Takao Fukuda, Kensuke Yamamichi, Kyosuke Toyoda, Urara Tanaka, Karen Yotsumoto, Takaharu Taketomi, Fusanori Nishimura
American Journal of Molecular Biology (AJMB) , 2017, DOI: 10.4236/ajmb.2017.72009
Abstract: Periodontal diseases are chronic inflammation caused by particular types of bacteria and have been recognized as a cause of tooth loss in adults. These bacteria which invade periodontal tissue are phagocytosed mainly by monocytes and macrophages in this immune response, and will be presented to lymphocytes. Recently, therapies for regenerating periodontal tissues have been used extensively to treat periodontal disease, and in particular, enamel matrix derivative (EMD) is commonly used for such therapies in Japan. Amelogenin is a type of the extracellular matrix protein that accounts for 90% of the constituents of EMD. In this study, we carried out a detailed microarray analysis in order to evaluate a gene group involved in amelogenin stimuli in the human monocytic cell line U-937. Microarray analysis revealed that statistically significant changes were apparent in 273 genes (163 up-regulated and 110 down-regulated) subsequent to 4 h of amelogenin stimulation. The most highly enriched categories included “cell cycle”, “DNA replication”, and “DNA repair” in up-regulated annotation terms. On the other hand, “type I diabetes mellitus”, “allograft rejection”, and “graft versus host disease” were observed in down-regulated annotation terms. Specifically, the gene expression of major to compatibility complex (MHC) class I/II and CD80/86 was impaired in U937 cells after stimulation with amelogenin. In addition, the results of heat-map showed that the gene expression of inflammatory cytokine such as tumor necrosis factor (TFN), interleukin-18 (IL-18), and CXCL16 was markedly decreased after stimulation of monocytes with amelogenin. In conclusion, the findings of our study showed that by inducing monocyte growth through the suppression of the antigen-presenting ability of U937 cells, amelogenin may affect the immune responses of periodontal tissues originating from monocytes. Examining the effects of amelogenin on the transformation of macrophages differentiating from monocytes may establish a molecular basis for the anti-inflammatory effect of amelogenin in periodontal tissues.
Heuristic Segmentation of a Nonstationary Time Series
Kensuke Fukuda,H. Eugene Stanley,Luis A. Nunes Amaral
Physics , 2003, DOI: 10.1103/PhysRevE.69.021108
Abstract: Many phenomena, both natural and human-influenced, give rise to signals whose statistical properties change under time translation, i.e., are nonstationary. For some practical purposes, a nonstationary time series can be seen as a concatenation of stationary segments. Using a segmentation algorithm, it has been reported that for heart beat data and Internet traffic fluctuations--the distribution of durations of these stationary segments decays with a power law tail. A potential technical difficulty that has not been thoroughly investigated is that a nonstationary time series with a (scale-free) power law distribution of stationary segments is harder to segment than other nonstationary time series because of the wider range of possible segment sizes. Here, we investigate the validity of a heuristic segmentation algorithm recently proposed by Bernaola-Galvan et al. by systematically analyzing surrogate time series with different statistical properties. We find that if a given nonstationary time series has stationary periods whose size is distributed as a power law, the algorithm can split the time series into a set of stationary segments with the correct statistical properties. We also find that the estimated power law exponent of the distribution of stationary-segment sizes is affected by (i) the minimum segment size, and (ii) the ratio of the standard deviation of the mean values of the segments, and the standard deviation of the fluctuations within a segment. Furthermore, we determine that the performance of the algorithm is generally not affected by uncorrelated noise spikes or by weak long-range temporal correlations of the fluctuations within segments.
Dynamic Resource Allocation and QoS Control Capabilities of the Japanese Academic Backbone Network
Shigeo Urushidani,Kensuke Fukuda,Michihiro Koibuchi,Motonori Nakamura,Shunji Abe,Yusheng Ji,Michihiro Aoki,Shigeki Yamada
Future Internet , 2010, DOI: 10.3390/fi2030295
Abstract: Dynamic resource control capabilities have become increasingly important for academic networks that must support big scientific research projects at the same time as less data intensive research and educational activities. This paper describes the dynamic resource allocation and QoS control capabilities of the Japanese academic backbone network, called SINET3, which supports a variety of academic applications with a wide range of network services. The article describes the network architecture, networking technologies, resource allocation, QoS control, and layer-1 bandwidth on-demand services. It also details typical services developed for scientific research, including the user interface, resource control, and management functions, and includes performance evaluations.
The Effects of Opening Trade on Regional Inequality in a Model of Scale-Invariant Growth and Foot-Loose Capital  [PDF]
Katsufumi Fukuda
Theoretical Economics Letters (TEL) , 2012, DOI: 10.4236/tel.2012.25078
Abstract: We consider a semi endogenous R & D growth model with international trade, foot-loose capital, and local and international knowledge spillovers in a closed economy and also international knowledge spillovers in an open economy. We show that by opening trade two regions diverge (converge) with (not) sufficiently high intertemporal knowledge spillover in the R & D sector and elasticity of substitution between modern goods, and not sufficiently high (sufficiently high) richer country A’s share of firm owned.
Osteoconductivity Control Based on the Chemical Properties of the Implant Surface  [PDF]
Kensuke Kuroda, Masazumi Okido
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2018, DOI: 10.4236/jbnb.2018.91003
Abstract: Metallic materials, such as Ti, Zr, Nb, Ta, and their alloys, and also stainless steels are widely attractive as osteoconductive materials in the dental and orthopedic fields. Ceramics and polymers are also commonly used as biomaterials. However, they do not have high osteoconductivity in their pure form, and surface coatings with bioactive substances, such as hydroxyapatite or TiO2, are needed before implantation into the bone. Many reports claim that the surface chemical properties of implants, in particular, hydrophilicity and hydrophobicity, strongly affect the biological reactions. However, the effect of surface properties on osteoconductivity is not clear. In this review, we focus on the relationship between the surface hydrophilicity of metallic implants and osteoconductivity using in vivo evaluation, and the control of the osteoconductivity is discussed from the viewpoint of protein adsorption in implants.
Human Pentraxin 3 (PTX3) as a Novel Biomarker for the Diagnosis of Pulmonary Arterial Hypertension
Yuichi Tamura, Tomohiko Ono, Masataka Kuwana, Kenji Inoue, Makoto Takei, Tsunehisa Yamamoto, Takashi Kawakami, Jun Fujita, Masaharu Kataoka, Kensuke Kimura, Motoaki Sano, Hiroyuki Daida, Toru Satoh, Keiichi Fukuda
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0045834
Abstract: Background Although inflammation is an important feature of pulmonary arterial hypertension (PAH), the usefulness of local inflammatory markers as biomarkers for PAH is unknown. In this study, we tested whether plasma concentrations of human pentraxin 3 (PTX3), a local inflammatory marker, would be a useful biomarker for detecting PAH. Methods Plasma PTX3 concentrations were evaluated in 50 PAH patients (27 with idiopathic PAH, 17 with PAH associated with connective tissue disease (CTD-PAH), and six with congenital heart disease), 100 age and sex-matched healthy controls, and 34 disease-matched CTD patients without PAH. Plasma concentrations of B-type natriuretic peptide (BNP) and C-reactive protein (CRP) were also determined. Results Mean PTX3 levels were significantly higher in all PAH patients than in the healthy controls (4.40±0.37 vs. 1.94±0.09 ng/mL, respectively; P<0.001). Using a threshold level of 2.84 ng/mL, PTX3 yielded a sensitivity of 74.0% and a specificity of 84.0% for the detection of PAH. In CTD-PAH patients, mean PTX3 concentrations were significantly higher than in CTD patients without PAH (5.02±0.69 vs. 2.40±0.14 ng/mL, respectively; P<0.001). There was no significant correlation between plasma levels of PTX3 and BNP or CRP. Receiver operating characteristic (ROC) curves for screening PAH in patients with CTD revealed that PTX3 (area under the ROC curve 0.866) is superior to BNP. Using a PTX3 threshold of 2.85 ng/mL maximized true-positive and false-negative results (sensitivity 94.1%, specificity 73.5%). Conclusion Plasma concentrations of PTX3 may be a better biomarker of PAH than BNP, especially in patients with CTD.
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